Dear Group,
using Mathematica 5.0 on WinXP I have a strange problem with
ListDensityPlot.
I have imported a picture (PNG) using
img=Import["mypic.png"];
I can show it, all fine so far.
I then extract the pixel data (rgb in this case) using
raster=img//First//First;
I extract the red channel using
rc=Map[First,raster,{2}];
and can display it with
ListDensityPlot[rc];
However, when I convert the raster to Lab color space and extract, say
the illumination
ListDensityPlot[lc];
fails with
"DensityGraphics::gmat: ... is not a rectangular array larger than 2 x
2"
But the size is identical to rc according to
Dimension[rc] is equal to Dimension[lc] : {400,300}.
Just Reals instead of Integers -- and though, rounding/scaling does not
make a difference.
I have checked the array using
Union[Length/@lc]
which evaluates to {400} in this case -- doesn't this say it _is_
rectangular? Do I miss something?
I can show part of the array using Take and define a region of at most
200x200 pixels -- expanding it again pops the error. I can move that
"window" over the image without errors.
Just expanding it does not work.
Any idea what could cause the problem? ( yes, I did restart windows ;)
Best Regards,
Peter